The problem with this mod is that it is easy to get to 300% productivity depending on what level you are on regarding of research (if the research only requires red research). Can it be balanced to include milestone requirements for all research types (i.e. if you get to level 3 of iron plates, it now requires green science, then gray science (at level 4), then blue science (at level 5), then purple (level 6), then yellow at level 7 (calling it by color of science), then after that, it requires space science at level 8 and other science packs onwards at more expensive rates - if sciences start with more different types of science packs at the start, same thing. It balances things out so you don't easily get the max research early, but requires you to play the game to max things out.

Right now the mod just takes the science packs from the research unlocking the item recipe, because there is no defined pack progression and just adding packs might make things un-researchable (I think there is at least one mod that adds basic science packs which are not present in normal labs). So, it's not completely clear how to do what you want.

I will think about it.

Technically once you research the next pack, you can continue with the research of that research until the next milestone.

What is the "next research pack"? I really don't want to hardcode progression.